Last reviewed 1 December 2021

Workplaces are normally safe places with good fire-related policies and procedures that are intended to eliminate or reduce the number of unwanted fire incidents. This includes false alarms and actual fires that may occur.

However, there may be occasions when such events do occur. In these circumstances the responsible person for fire safety must ensure that appropriate action is taken in relation to the recording, reporting and investigation of the unwanted incidents.

This is to ensure that legislative requirements are met and to enable lessons to be learnt that may prevent similar events from occurring.

Why investigate?

Under Article 11 of the Regulatory Reform (Fire Safety) Order 2005 (or the respective equivalents in Scotland and Northern Ireland), the responsible person “must make and give effect to such arrangements as are appropriate... for the effective planning, organisation, control, monitoring and review of the preventive and protective measures”.

Although this article does not specifically require the investigation of unwanted fire incidents, it does require the responsible person to have a system that ensures the fire prevention and precautions measures are operating as intended.

Clearly, an unwanted event suggests such measures may not be operating as intended and some form of investigation is necessary to determine why.

BS9997: Fire risk management systems — Requirements with guidance for use, recommends that in the event of an incident, in order to prevent recurrence or occurrence elsewhere, the organisation should:

  • evaluate the need for action to eliminate the causes of the incident

  • implement any action needed

  • review the effectiveness of any corrective action taken.

In doing so, BS9997 highlights that evaluation would require:

  • reviewing and analysing the incident

  • determining the causes of the incident

  • determining if similar incidents could potentially occur.

Undertaking investigations of unwanted fire incidents will bring a number of benefits including:

  • meeting legislative requirements/reducing potential for enforcement action

  • preventing further similar incidents from occurring/recurring

  • preventing unnecessary business disruptions and associated costs

  • indicating to stakeholders that fire safety is taken seriously

  • reducing fire and rescue service costs of attendance

  • satisfying insurance requirements.

False alarms

If an automatic fire-detection and fire-alarm system (FDAS) is used and maintained properly, its fast response to a fire that is just beginning can greatly reduce the risk to life and limit damage to property.

However, in a typical year, a third of all fire calls received by fire and rescue services (FRS) are false alarms caused by fire detection and alarm systems. Typical causes of false alarms are:

  • pollutants in the air setting off smoke detectors (eg dust, aerosols and insects)

  • extremely high temperatures setting off heat detectors (eg from hot work activities)

  • vandalism or malicious acts (such as setting off break glass call points)

  • mistakes occurring in the use of the system

  • the equipment being faulty or not being maintained properly

  • fire detectors or red “break glass” boxes being in the wrong place and being accidentally set off.

This high proportion of false alarms has a significant impact on local fire services, reducing their availability to attend actual incidents and creating substantial financial burdens on the FRS.

Although it is recognised that false alarms will occur, failure to reduce these to a reasonable level could have implications including:

  • enforcement action under the relevant legislative requirement

  • costs being incurred by the FRS charging to attend false alarms

  • reduced and/or extended attendance times by the FRS.

BS 5839-1: Fire detection and alarm systems for buildings. Code of practice for design, installation, commissioning and maintenance of systems in non-domestic premises, gives a great deal of attention to minimising false alarms.

It highlights that “it is incumbent on the user to ensure that the system and the building itself are suitably managed to avoid unnecessary false alarms” and if they do occur at an unacceptable level ensure “appropriate steps are taken to reduce the rate at which they occur”.

A preliminary investigation should be undertaken to determine the cause/s of the actuations. A team approach is advocated to ensure there is detailed knowledge of the FDAS and familiarity with good fire safety practice, along with legal requirements. This investigative review should determine the causes of false alarms and then analyse whether further risk control measures are required including:

  • siting and selection of manual call points and fire detectors

  • installation of deterrence devices (eg call point covers and CCTV monitoring)

  • protection against electromagnetic interference

  • performance monitoring of newly commissioned systems

  • filtering measures (eg staff alarm arrangements)

  • system management (eg staff awareness and control of contractors)

  • regular servicing and maintenance.

Fire incidents

In the event of an actual fire incident, primacy for any fire investigation will rest with the relevant police and/or fire and rescue service.

The Fire and Rescue Services Act 2004 provides formal powers for fire and rescue services to investigate the causes of fires and the reasons for fire spread. These powers, (which are balanced by safeguards for the public), may be used in cases where permission for fire investigation cannot be obtained from, or are withheld by, the person responsible for the premises in question.

Special considerations apply in the case of suspicious fires that are the subject of a police investigation. Where a fire is thought to be suspicious, the fire officer in charge at the scene of the fire will ensure that the scene is preserved and undisturbed as far as possible and will immediately report, or have reported any suspicions and will in inform the police.

There are various levels of fire investigation that the FRS/police may undertake, depending on the type of incident and its seriousness. In summary the investigation will strive to:

  • determine the origin of the fire: this involves an assessment of factors which may include indicators such as electrical evidence, witness evidence, burn and smoke patterns, the fire load, fire-fighting activities and ventilation and temperature indicators

  • identify the cause of the fire: this involves an assessment of all viable ignition sources in each individual case. This includes consideration of all realistic sources pertinent to the specific incident.

As part of the investigation the police and/or fire and rescue service may formally interview any witnesses to the fire event and request any relevant documentation from the organisation that is relevant to the investigation.

On completion of the investigation, an FDR1 report would be developed and submitted to the relevant Government department.

The organisation itself may wish to undertake a formal investigation, depending on the findings of the FRS/police investigation. In summary this may enable determination of:

  • the facts and sequence of events leading to the fire

  • the causes by establishing any unsafe acts or conditions that could have resulted in the fire occurring

  • the human, organisational and/or job factors that gave rise to the unsafe acts and/or conditions.

This will enable the organisation to achieve the benefits of investigation of unwanted events as noted above.


Organisations may experience various unwanted fire-related incidents. This can include actual fires but also incidents such as false alarms.

The investigation of both is necessary to ensure that the organisation is meeting its legal obligations and has in place the required fire risk control measures.

Investigations also make good business sense as they will also reduce future disruptions and associated costs. In summary, a robust investigation will involve:

  • gathering the information to determine what happened and what conditions and actions influenced the unwanted event

  • analysing the information by examining all the facts, determining what happened and why

  • identifying risk control measures with ‘optimum’ solution/s being considered for implementation

  • the action plan and its implementation for determining risk control measures that should be implemented in the short and long term.

Further information

The following are available from the British Standards Institution:

  • BS9997: Fire risk management systems — Requirements with guidance for use

  • BS 5839-1: Fire detection and alarm systems for buildings. Code of practice for design, installation, commissioning and maintenance of systems in non-domestic premises.

The following are available from the National Fire Chiefs Council:

  • Reduction of False Alarms and Unwanted Fire Signals

  • Code of Practice for Investigators of Fires and Explosions for the Criminal Justice Systems in the UK.